Underreamer.



PATENTED DBG. z5, 1906.

J. P. THOMPSON.

UNDBRREAMBR.

aA`11"LI0ATI0N FILED FEB. 8. 1 906.

W/ TNE SSE S:

cal. wAsmNcraN, n. c.

UNITED STATES PATENT OFFICE.

JOSEPH FLANAGAN THOMPSON, OF MARIETTA, OHIO.

UNDER Application filed February To al?, whom, t nba/y concer-72,:

Be it known that I, JosEPi-i FLANAGAN THOMPSON, a citizen of the United States, and aresident of Marietta, in the county of VVashington and State of Ohio, have invented a new and Improved Underrearner, of which the following is a full, clear, and exact description.

My invention relates to an underreamer for oil-wells and the like, the principal objects being to provide means whereby the reamer can be lowered through a casing, automatically expanding when it reaches the end of the casing and having no parts extending materially below the working edges of the bits also, to provide a convenient and ellicient means for manipulating the bits for permitting the lowering of the reamer in the casing without interfering with the operation of the same when it reaches the lower end thereof to provide efficient means for holding the bits in expanded position when it is desired to operate the` device for reaming and to avoid vertical motion of the bits with respect to the body of the reamer.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the figures.

Figure 1 is a central longitudinal section of an instrument constructed in accordance with the principle of my invention, showing it in position while being lowered through the casing. Fig. 2 is a sectional view of the same, taken at right angles to Fig. 1. Fig. 3 is a sectional view similar to Fig. 2, showing the position of the parts when the bits are lowered to a position below the end of the cas-v ing. Fig. 4 is a sectional view on the line 4 4 of Fig. 1. Fig. 5 is an end elevation, and Fig. 6 is a side elevation, of a portion of the device, showing the bits in expanded position.

The instrument is provided with a cylindrical body 10, having notches 11 cut in the lower edge on the opposite sides thereof and slots 12 in the sides between the notches. At the rear of the notches are shoulders 13,and extending inwardly from the inner sides of these shoulders is a cavity 14, bounded on the rear by a wall, which is preferably flat. In these notches are located bits 15, these bits having extensions 16 projecting back into the cavity 14. These extensions are provided with perforations 17, in which engage pins 1S, mounted on the body 10, whereby vSpecification of Letters Patent.

FREAIVIER.

Patented Dec. 25, 1906.

8,1906. Serial No. 300.182.

the bits are, in effect, pivotally mounted on the body. Located between the bits is a wedge 19. This wedge is provided with a cap 20, and a rod 21 passes through the cap and wedge and through a perforation 22 in the body into a cavity 23 at the rear of the cavity 14. Threaded on this rod is a sleeve 24, which is provided with a collar 25, the two ends of the rod being provided with nuts or a nut and head to secure the parts in osition. Located between the collar 25 ant the lower end of the cavity 23 is a sprin T 26 for normally forcing the wedge inwardly and thus spreading the bits into an outer position. For the purpose of assisting in manipulating these parts T have provided the wedge with a pair of notches 27, and over these notches pass projections 28 on resilient plates 29, which are capable of sliding between tlie wedge and the body of the cylinder and terminate in projections 30. These proj ections are undercut, so as to provide a surface 31 for engaging raised surfaces 32, located in each of the slots 12. The surfaces 31 and 32 are curved at their meeting ends, soas to provide for a convenient operation.

My preferred construction having been described, I will now state the manner in which it operates.

When a well is cased, the hole below the casing is of the same size as the inside diaineter of the casing. In using an underreainer it is necessary to lift the casing-bottom and raise it eight or ten feet. This leaves a hole below the bottom of the casing the same size as the exterior of the casing and gives the bits a chance to expand. is lowered within the casing, the parts assume the position shown in Figs. 1 and 2. The projections 30 bear against the inside of the casing, and as the outer surfaces of the bits also bear against this surface the wedge is prevented from moving upwardly, and consequently the projections 30 are held in the position indicated in Fig. 1 until the bits are lowered sul'lciently to project from the bottoni of the casing. This permits the wedge to be drawn upwardly by the spring 26 and the projections 30 to move upwardly with it. The surfaces 31 then ride upon the surfaces 32, and the latter acts as stops to prevent the projections froin being forced toward the center of the cylinder. Vhen the parts are in this position, as shown in Figs. 3 and 6, the cap 20 rests on shoulders 53 ICO ICS

IIO

vof the cavity 14.

on the bits, and rear shoulders 34 also on the bits rest on the shoulders 13 of the slots 11. The rear ends hof the bits also engage the rear This construction is such that the bits are securely held in dposition and prevented from moving upwar ly with respect to theucasing. It will be seen that when the parts are in working position there is nothing to project any material distance below the working points of the bits, and they can operate to the bottom of the well. This in itself is a great improvement over reamers heretofore known in this art, as they have not been constructed in such a manner as to permit operations to the bottom of the well. As will be obvious, the operation of the device is entirely automatic, the bits beforced outwardly the instant the reamer is owered through the bottom of the casing, and the parts are securely held in position for operation during all manipulations of the instrument. Vhen it is desired to withdraw the reamer, it is simply pulled up, and, the lower edge of the casing engaging the outer surfaces of the projections 30 before it engages the bits, the wedge will be lowered with respect to the casing to permit the bits to move inwardly when they are drawn into the lower end of the casing. The device can also be readily taken to pieces and the parts easily removed and renewed.

It will be observed that by my invention all vertical motion of the bits with respect to the body of the reamer is avoided, and the bits have positive and unyielding bearingsurfaces. Y

It will be noticed that the ends of the slots 12 are beveled in such a manner as to prevent the lodgment of dirt, and at least avoid the packing of dirt in this place, which would interfere with the operation of the instrument.

Having thus described my invention, I claim- 1. An underreamer having 'a body portion provided with a cavity in the end thereof, the wall of the cavity having oppositelyarranged slots and having oppositely-arranged notches at the lower edge thereof, bits within the notches, said bits having shoulders for engaging the ends of the notches, a wedge between the bits, a spring acting to move the wedge upwardly whereby to project the bits through the notches, springplates upon' the wedge, said plates having projections normally extending through the slots, said projections being undercut, and cam-surfaces on the walls of the slots upon which the projections ride when the wedge is moved upward by the spring, said camsurfaces and projections engaging when the projections are forced inward bythe wallcasing to prevent the said riding action of the projection whereby to prevent the upward movement of the wedge.

2. An underreamer having a body portion provided in the end thereof with acavity having slotted and notched walls, bits within the notches and having a shoulder for engaging the ends thereof, a wedge between the bits, a spring normally acting to force the. wedge upward whereby to project the bits beyond the outer face of the body, spring-plates upon the wedge having undercut projections normally extending through the slots, and cam-surfaces on the walls of the slots upon which said projections ride `when the wedge is moi/'ed upward.

3. An underreamer comprising a body and bits movable in the body, a longitudinally-movable spring-actuated wedge for forcing the edge of the bits beyond the periph-.

eral face of the body, spring-plates secured to the wedge and provided with projections normally extending beyond the peripheral face of the body, and means connected with the body for engaging the projections when Athey are forced inward, whereby to prevent the movement of the Wedge.

4. An underreamer comprising a body, bits movably mounted therein, means for controlling the position of said bits, said means comprising reciprocable plates having projections extending through the side of said body and adapted to engage the wall of the well-casing, said body having means for holding the projections in outward position while the body is without the casing.

5. An underreamer comprising a body having slots through its walls, bits extending through said slots a cam-surface projecting inwardly from each of said slots, a device for controlling said bits, comprising plates having projections extending through the slots, said projections having undercut surfaces adapted to engage said cam-surfaces in the slots whereby the projections are forced outwardly beyond the surface of the body portion.

6. An underreamer comprising a body, bits mounted on said body, a wedge located in the interior of said body for forcing the bits outwardly, a plate connected with said wedge and having a projection, said body having a slot through which said projection extends, said slot having a portion, through the bottom of which, the projection is adapted to pass, and having means for preventing the projection from passing inwardly when the latter is at one end of the slot.

7. An underreamer comprising a cylindrical body having a passage therethrough, a plurality of bits located in said passage, said body having pins for holding said bits in position on the body, a wedge located in said passage and adapted to force the bits out- IOO IIO

body to the pas-sage at one end7 and the In testimony whereof I have signed Iny other end having a raised surface for engaging naine. to this specification in the presence of a surface on said projection and holding the I two subscribing Witnesses.

projection in such position that its surface i JOSEPH FLANAGAN THOMPSON. 5 projects beyond the surface of the body, and /Vitnesses:

zt spring for normally forcing said Wedge n- RUFUS A. UNDERWOOD,

Wardly. t S. M. FLANEGIN. 

